/*
 * bzip2 is written by Julian Seward <jseward@bzip.org>.
 * Adapted for busybox by Denys Vlasenko <vda.linux@googlemail.com>.
 * See README and LICENSE files in this directory for more information.
 */

/*-------------------------------------------------------------*/
/*--- Library top-level functions.                          ---*/
/*---                                               bzlib.c ---*/
/*-------------------------------------------------------------*/

/* ------------------------------------------------------------------
This file is part of bzip2/libbzip2, a program and library for
lossless, block-sorting data compression.

bzip2/libbzip2 version 1.0.4 of 20 December 2006
Copyright (C) 1996-2006 Julian Seward <jseward@bzip.org>

Please read the WARNING, DISCLAIMER and PATENTS sections in the
README file.

This program is released under the terms of the license contained
in the file LICENSE.
------------------------------------------------------------------ */

/* CHANGES
 * 0.9.0    -- original version.
 * 0.9.0a/b -- no changes in this file.
 * 0.9.0c   -- made zero-length BZ_FLUSH work correctly in bzCompress().
 *             fixed bzWrite/bzRead to ignore zero-length requests.
 *             fixed bzread to correctly handle read requests after EOF.
 *             wrong parameter order in call to bzDecompressInit in
 *             bzBuffToBuffDecompress.  Fixed.
 */

/* #include "bzlib_private.h" */

/*---------------------------------------------------*/
/*--- Compression stuff                           ---*/
/*---------------------------------------------------*/

/*---------------------------------------------------*/
#if BZ_LIGHT_DEBUG
static
void bz_assert_fail(int errcode)
{
        /* if (errcode == 1007) bb_error_msg_and_die("probably bad RAM"); */
        bb_error_msg_and_die("internal error %d", errcode);
}
#endif

/*---------------------------------------------------*/
static
void prepare_new_block(EState* s)
{
        int i;
        s->nblock = 0;
        //indexes into s->zbits[], initialzation moved to init of s->zbits
        //s->posZ = s->zbits; // was: s->numZ = 0;
        //s->state_out_pos = s->zbits;
        BZ_INITIALISE_CRC(s->blockCRC);
        /* inlined memset would be nice to have here */
        for (i = 0; i < 256; i++)
                s->inUse[i] = 0;
        s->blockNo++;
}


/*---------------------------------------------------*/
static
ALWAYS_INLINE
void init_RL(EState* s)
{
        s->state_in_ch = 256;
        s->state_in_len = 0;
}


static
int isempty_RL(EState* s)
{
        return (s->state_in_ch >= 256 || s->state_in_len <= 0);
}


/*---------------------------------------------------*/
static
void BZ2_bzCompressInit(bz_stream *strm, int blockSize100k)
{
        unsigned n;
        EState* s;

        s = xzalloc(sizeof(EState));
        s->strm = strm;

        n        = 100000 * blockSize100k;
        s->arr1  = xmalloc(n                    * sizeof(uint32_t));
        s->mtfv  = (uint16_t*)s->arr1;
        s->ptr   = (uint32_t*)s->arr1;
        s->arr2  = xmalloc((n + BZ_N_OVERSHOOT) * sizeof(uint32_t));
        s->block = (uint8_t*)s->arr2;

        crc32_filltable(s->crc32table, 1);

        s->state             = BZ_S_INPUT;
        s->mode              = BZ_M_RUNNING;
        s->blockSize100k     = blockSize100k;
        s->nblockMAX         = n - 19;

        strm->state          = s;
        /*strm->total_in     = 0;*/
        strm->total_out      = 0;
        init_RL(s);
        prepare_new_block(s);
}


/*---------------------------------------------------*/
static
void add_pair_to_block(EState* s)
{
        int32_t i;
        uint8_t ch = (uint8_t)(s->state_in_ch);
        for (i = 0; i < s->state_in_len; i++) {
                BZ_UPDATE_CRC(s, s->blockCRC, ch);
        }
        s->inUse[s->state_in_ch] = 1;
        switch (s->state_in_len) {
                case 3:
                        s->block[s->nblock] = (uint8_t)ch; s->nblock++;
                        /* fall through */
                case 2:
                        s->block[s->nblock] = (uint8_t)ch; s->nblock++;
                        /* fall through */
                case 1:
                        s->block[s->nblock] = (uint8_t)ch; s->nblock++;
                        break;
                default:
                        s->inUse[s->state_in_len - 4] = 1;
                        s->block[s->nblock] = (uint8_t)ch; s->nblock++;
                        s->block[s->nblock] = (uint8_t)ch; s->nblock++;
                        s->block[s->nblock] = (uint8_t)ch; s->nblock++;
                        s->block[s->nblock] = (uint8_t)ch; s->nblock++;
                        s->block[s->nblock] = (uint8_t)(s->state_in_len - 4);
                        s->nblock++;
                        break;
        }
}


/*---------------------------------------------------*/
static
void flush_RL(EState* s)
{
        if (s->state_in_ch < 256) add_pair_to_block(s);
        init_RL(s);
}


/*---------------------------------------------------*/
#define ADD_CHAR_TO_BLOCK(zs, zchh0) \
{ \
        uint32_t zchh = (uint32_t)(zchh0); \
        /*-- fast track the common case --*/ \
        if (zchh != zs->state_in_ch && zs->state_in_len == 1) { \
                uint8_t ch = (uint8_t)(zs->state_in_ch); \
                BZ_UPDATE_CRC(zs, zs->blockCRC, ch); \
                zs->inUse[zs->state_in_ch] = 1; \
                zs->block[zs->nblock] = (uint8_t)ch; \
                zs->nblock++; \
                zs->state_in_ch = zchh; \
        } \
        else \
        /*-- general, uncommon cases --*/ \
        if (zchh != zs->state_in_ch || zs->state_in_len == 255) { \
                if (zs->state_in_ch < 256) \
                        add_pair_to_block(zs); \
                zs->state_in_ch = zchh; \
                zs->state_in_len = 1; \
        } else { \
                zs->state_in_len++; \
        } \
}


/*---------------------------------------------------*/
static
void /*Bool*/ copy_input_until_stop(EState* s)
{
        /*Bool progress_in = False;*/

#ifdef SAME_CODE_AS_BELOW
        if (s->mode == BZ_M_RUNNING) {
                /*-- fast track the common case --*/
                while (1) {
                        /*-- no input? --*/
                        if (s->strm->avail_in == 0) break;
                        /*-- block full? --*/
                        if (s->nblock >= s->nblockMAX) break;
                        /*progress_in = True;*/
                        ADD_CHAR_TO_BLOCK(s, (uint32_t)(*(uint8_t*)(s->strm->next_in)));
                        s->strm->next_in++;
                        s->strm->avail_in--;
                        /*s->strm->total_in++;*/
                }
        } else
#endif
        {
                /*-- general, uncommon case --*/
                while (1) {
                        /*-- no input? --*/
                        if (s->strm->avail_in == 0) break;
                        /*-- block full? --*/
                        if (s->nblock >= s->nblockMAX) break;
                //#     /*-- flush/finish end? --*/
                //#     if (s->avail_in_expect == 0) break;
                        /*progress_in = True;*/
                        ADD_CHAR_TO_BLOCK(s, *(uint8_t*)(s->strm->next_in));
                        s->strm->next_in++;
                        s->strm->avail_in--;
                        /*s->strm->total_in++;*/
                //#     s->avail_in_expect--;
                }
        }
        /*return progress_in;*/
}


/*---------------------------------------------------*/
static
void /*Bool*/ copy_output_until_stop(EState* s)
{
        /*Bool progress_out = False;*/

        while (1) {
                /*-- no output space? --*/
                if (s->strm->avail_out == 0) break;

                /*-- block done? --*/
                if (s->state_out_pos >= s->posZ) break;

                /*progress_out = True;*/
                *(s->strm->next_out) = *s->state_out_pos++;
                s->strm->avail_out--;
                s->strm->next_out++;
                s->strm->total_out++;
        }
        /*return progress_out;*/
}


/*---------------------------------------------------*/
static
void /*Bool*/ handle_compress(bz_stream *strm)
{
        /*Bool progress_in  = False;*/
        /*Bool progress_out = False;*/
        EState* s = strm->state;

        while (1) {
                if (s->state == BZ_S_OUTPUT) {
                        /*progress_out |=*/ copy_output_until_stop(s);
                        if (s->state_out_pos < s->posZ) break;
                        if (s->mode == BZ_M_FINISHING
                        //# && s->avail_in_expect == 0
                         && s->strm->avail_in == 0
                         && isempty_RL(s))
                                break;
                        prepare_new_block(s);
                        s->state = BZ_S_INPUT;
#ifdef FLUSH_IS_UNUSED
                        if (s->mode == BZ_M_FLUSHING
                         && s->avail_in_expect == 0
                         && isempty_RL(s))
                                break;
#endif
                }

                if (s->state == BZ_S_INPUT) {
                        /*progress_in |=*/ copy_input_until_stop(s);
                        //#if (s->mode != BZ_M_RUNNING && s->avail_in_expect == 0) {
                        if (s->mode != BZ_M_RUNNING && s->strm->avail_in == 0) {
                                flush_RL(s);
                                BZ2_compressBlock(s, (s->mode == BZ_M_FINISHING));
                                s->state = BZ_S_OUTPUT;
                        } else
                        if (s->nblock >= s->nblockMAX) {
                                BZ2_compressBlock(s, 0);
                                s->state = BZ_S_OUTPUT;
                        } else
                        if (s->strm->avail_in == 0) {
                                break;
                        }
                }
        }

        /*return progress_in || progress_out;*/
}


/*---------------------------------------------------*/
static
int BZ2_bzCompress(bz_stream *strm, int action)
{
        /*Bool progress;*/
        EState* s;

        s = strm->state;

        switch (s->mode) {
                case BZ_M_RUNNING:
                        if (action == BZ_RUN) {
                                /*progress =*/ handle_compress(strm);
                                /*return progress ? BZ_RUN_OK : BZ_PARAM_ERROR;*/
                                return BZ_RUN_OK;
                        }
#ifdef FLUSH_IS_UNUSED
                        else
                        if (action == BZ_FLUSH) {
                                //#s->avail_in_expect = strm->avail_in;
                                s->mode = BZ_M_FLUSHING;
                                goto case_BZ_M_FLUSHING;
                        }
#endif
                        else
                        /*if (action == BZ_FINISH)*/ {
                                //#s->avail_in_expect = strm->avail_in;
                                s->mode = BZ_M_FINISHING;
                                goto case_BZ_M_FINISHING;
                        }

#ifdef FLUSH_IS_UNUSED
 case_BZ_M_FLUSHING:
                case BZ_M_FLUSHING:
                        /*if (s->avail_in_expect != s->strm->avail_in)
                                return BZ_SEQUENCE_ERROR;*/
                        /*progress =*/ handle_compress(strm);
                        if (s->avail_in_expect > 0 || !isempty_RL(s) || s->state_out_pos < s->posZ)
                                return BZ_FLUSH_OK;
                        s->mode = BZ_M_RUNNING;
                        return BZ_RUN_OK;
#endif

 case_BZ_M_FINISHING:
                /*case BZ_M_FINISHING:*/
                default:
                        /*if (s->avail_in_expect != s->strm->avail_in)
                                return BZ_SEQUENCE_ERROR;*/
                        /*progress =*/ handle_compress(strm);
                        /*if (!progress) return BZ_SEQUENCE_ERROR;*/
                        //#if (s->avail_in_expect > 0 || !isempty_RL(s) || s->state_out_pos < s->posZ)
                        //#     return BZ_FINISH_OK;
                        if (s->strm->avail_in > 0 || !isempty_RL(s) || s->state_out_pos < s->posZ)
                                return BZ_FINISH_OK;
                        /*s->mode = BZ_M_IDLE;*/
                        return BZ_STREAM_END;
        }
        /* return BZ_OK; --not reached--*/
}


/*---------------------------------------------------*/
static
void BZ2_bzCompressEnd(bz_stream *strm)
{
        EState* s;

        s = strm->state;
        free(s->arr1);
        free(s->arr2);
        //free(s->ftab);       // made it array member of s
        //free(s->crc32table); // ditto
        free(s);
}


/*---------------------------------------------------*/
/*--- Misc convenience stuff                      ---*/
/*---------------------------------------------------*/

/*---------------------------------------------------*/
#ifdef EXAMPLE_CODE_FOR_MEM_TO_MEM_COMPRESSION
static
int BZ2_bzBuffToBuffCompress(char* dest,
                unsigned int* destLen,
                char*         source,
                unsigned int  sourceLen,
                int           blockSize100k)
{
        bz_stream strm;
        int ret;

        if (dest == NULL || destLen == NULL
         || source == NULL
         || blockSize100k < 1 || blockSize100k > 9
        ) {
                return BZ_PARAM_ERROR;
        }

        BZ2_bzCompressInit(&strm, blockSize100k);

        strm.next_in = source;
        strm.next_out = dest;
        strm.avail_in = sourceLen;
        strm.avail_out = *destLen;

        ret = BZ2_bzCompress(&strm, BZ_FINISH);
        if (ret == BZ_FINISH_OK) goto output_overflow;
        if (ret != BZ_STREAM_END) goto errhandler;

        /* normal termination */
        *destLen -= strm.avail_out;
        BZ2_bzCompressEnd(&strm);
        return BZ_OK;

 output_overflow:
        BZ2_bzCompressEnd(&strm);
        return BZ_OUTBUFF_FULL;

 errhandler:
        BZ2_bzCompressEnd(&strm);
        return ret;
}
#endif

/*-------------------------------------------------------------*/
/*--- end                                           bzlib.c ---*/
/*-------------------------------------------------------------*/